These entities were added to the HTML definition as of HTML 4. The Relevant ISO standard defining the entity name is given unless the names were newly introduced with HTML 4. These entity names are not supported by Netscape Communicator 4, but are supported by Internet Explorer 4.
NOTE -- There is a useful Table Key at the bottom of this document.
| Character # (Decimal) | Character # (Hex) | Character Reference | Entity Name | Entity Reference | Description | ISO Standard |
| Mathematical Operators | ||||||
| 8712 | 2208 | ∈ | isin | ∈ | element of | ISOtech |
| 8713 | 2209 | ∉ | notin | ∉ | not an element of | ISOtech |
| 8715 | 220B | ∋ | ni | ∋ | contains as member | ISOtech |
| 8734 | 221E | ∞ | infin | ∞ | infinity | ISOtech |
| 8745 | 2229 | ∩ | cap | ∩ | intersection=cap, | ISOtech |
| 8746 | 222A | ∪ | cup | ∪ | union=cup, | ISOtech |
| 8800 | 2260 | ≠ | ne | ≠ | not equal to | ISOtech |
| 8801 | 2261 | ≡ | equiv | ≡ | identical to | ISOtech |
| 8804 | 2264 | ≤ | le | ≤ | less-than or equal to | ISOtech |
| 8805 | 2265 | ≥ | ge | ≥ | greater-than or equal to | ISOtech |
| 8834 | 2282 | ⊂ | sub | ⊂ | subset of | ISOtech |
| 8835 | 2283 | ⊃ | sup | ⊃ | superset of | ISOtech |
| 8836 | 2284 | ⊄ | nsub | ⊄ | not a subset of | ISOamsn |
| 8838 | 2286 | ⊆ | sube | ⊆ | subset of or equal to | ISOtech |
| 8839 | 2287 | ⊇ | supe | ⊇ | superset of or equal to | ISOtech |